Flexible starter bar for continuous casting

ABSTRACT

The flexible starter bar of the invention comprises a rigid head portion connected with an elongated flexible body portion. The body portion includes continuous flat thin steel facing pieces spaced apart by a multiplicity of spacing members therebetween, which are strung on a flexible retaining rod connected to the head portion. A slidable connector provides a means for pulling the bar through the bending rolls. An alternative embodiment includes a hinged chillbox for ease in traversing a curved guide roll system.

United States Patent 72] Inventor Richard E. Lyman Homewood, Ill.

[2]] Appl. No. 38,461 [22] Filed May 18, 1970 [45] Patented Jan. 11, 1972 [73] Assignee United States Steel Corporation [54] FLEXIBLE STARTER BAR FOR CONTINUOUS CASTING 10 Claims, 11 Drawing Figs.

[52] US. Cl 164/274 [51] ...B22d 11/08 [50} Field of Search 164/82,

[5 6] References Cited UNITED STATES PATENTS 2,920,359 1/1960 Easton et a1. [64/274 X 3,351,124 11/1967 Hess 164/274 3,451,466 6/1969 Orr 164/274 FOREIGN PATENTS 1,379,352 10/1964 France 164/282 1,045,654 10/1966 Great Britain 164/274 Primary ExaminerR. Spencer Annear Attorney-Ralph A. Dougherty ABSTRACT: The flexible starter bar ofthe invention comprises a rigid head portion connected with an elongated flexible body portion. The body portion includes continuous flat thin steel facing pieces spaced apart by a multiplicity of spacing members therebetween, which are strung on a flexible retaining rod connected to the head portion. A slidable connector provides a means for pulling the bar through the bending rolls. An alternative embodiment includes a hinged chillbox for ease in traversing a curved guide roll system.

msmsn Jun 1 m SHEET 1 [IF 3 IN VEN TOR. RICHARD E. LYMAN A f forney PATENTED JAN] 1 H72 31633353 SHEET 2 BF 3 FIG. 8.

FIG. 7.

INVENTOR. RICHARD E. LYMAN Mm )JA AHK Aflorney PATENTED mu 1 I972 SHEET 3 BF 3 IN VE/V TOR.

R/ CHARD E. L YMAN mam, //aa Attorney FLEXIBLE STARTER BAR FOR CONTINUOUS CASTING The present invention relates generally to continuous-casting equipment and, more particularly, to an improved flexible starter bar for use with a continuous-casting mold.

Typical machines used for the continuous casting of metal products conventionally include a gravity flow, open end mold, which may be disposed vertically or inclined from the vertical, guide rolls, pinch rolls, bending rolls, and straightener rolls. The bending rolls are angularly displaced relative to the mold to bend the columnar casting descending from the mold into a curved path so it may eventually be delivered horizontally for cutting into required lengths. Examples of casting machines are disclosed by US. Pat. Nos. 2,920,359 and 2,904,860.

A starter bar is utilized for conducting the casting from the mold and starting it through the rolls. Where a rigid steel starter bar is used, it must be disconnected from the casting before the bar reaches the bending and straightening rolls. This necessary removal of the rigid starter bar presents a number of difficult problems since the bar is heavy and bulky and requires additional manpower and space for manipulation to effect its removal from the casting.

In efforts to avoid the problems inherent in the use of rigid starter bars, attempts were made to use solid starter bars made of relatively soft metals, such as aluminum, brass or the like. However, such attempts were unsuccessful since it was found that after each use of such a bar in a continuous-casting operation, including complete passage of the bar through the bending and straightening elements, the thickness of the bar was reduced and it became harder due to the compression and bending action of the pinch rolls, bending rolls and straightening rolls on the starter bar. This, of course, made the use of solid starter bars of relatively soft metal impractical.

Prior to my invention, starter bars made up of flexibly interlocking segments or of segments assembled on a flexible tie member were also used in an attempt to avoid the problems presented by use of solid starter bars. Examples of certain types of flexible starter bars are disclosed in US. Pat. Nos. 2,920,359; 3,305,899 and 3,324,934. Such starter bars were found not to be entirely satisfactory. They were difficult to handle and guide since they did not have the ability to withstand compression or side thrust. Such flexible starter bars had to be supported at close intervals to prevent them folding upon themselves as, for example, on a long runout table where the conveyor rollers are spaced relatively long distances apart. But more importantly, each segment of such flexible starter bars presents a flat face to the guide rolls and bending rolls. In addition, any opening between adjacent segments interferes with the continuous movement of the starter bar through the guide roll system.

A conventional mold stool, like a solid steel starter bar, introduces excessive stress to the rolls through which it passes, and tends to damage the roll. The cast steel immediately behind it is frozen stifi and is not pliable.

It is, accordingly, the primary object of my invention to provide an improved flexible starter bar which will present a smooth continuously curved surface, without flat spots, to the bending rolls regardless of the radius of curvature of the starter bar.

It is another object of my invention to provide a flexible starter bar which will remain straight and rigid enough to perform its required function of supporting its head in position as a temporary bottom of the mold of a continuous caster while molten metal is initially poured into the mold and thereafter remain rigid in the vertical plane during withdrawal of the starter bar from the bottom of the mold as casting proceeds, and yet be capable of being bent and straightened through the same bending and straightening rolls through which the casting is drawn by the starter bar without damage to either the rolls or the starter bar itself.

Another object of my invention is to provide means for pivotally attaching a chillbox to a starter bar so it may easily pass through a curved guide roll system without damaging the rolls through which it passes.

It is still another object of my invention to provide means for pulling a flexible starter bar through a curved guide roll system.

The improved starter bar of my invention comprises a relatively short rigid head and an elongated body joined together. The head is adapted to attach to a disposable mold stool which functions as a temporary bottom of the mold. The body supports the head and draws it, together with the casting, through the pinch rolls, bending rolls, and'straightening rolls. The body is composed of continuous facing pieces held in spaced-apart parallel relationship by means of a plurality of spaced, transversely extending spacer members disposed between the facing pieces. The facing pieces may be fabricated from steel plate or strip. One or more tie rods are attached to the head and extend through the spacer members between the facing pieces. This arrangement provides freedom of sliding movement between the contiguous surfaces of the facing pieces and the spacer members and thus renders the starter bar flexible as it moves through the various elements of the continuous-casting machine. The ends of the facing pieces remote from the head portion are bent toward each other to facilitate movement of the starter bar through the casting machine. Alternatively, the facing pieces each terminate in a pullingmember which imparts tensile stress only to the facing piece having the greater radius of curvature while retaining the proper position of the other piece.

A complete description of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating the several preferred embodiments.

In the drawings FIG. 1 is a diagrammatic elevational side view showing the starter bar of the invention in a continuouscasting machine;

FIG. 2 is a crosssectional view taken substantially along the line IIII of FIG. 1;

FIG. 3 is a plan view of a spacing member showing an alter native means for connecting the members of the articulated separator;

FIG. 4 is an end view of the spacer member of FIG. 3;

FIG. 5 is a partially cutaway front view of the top end of the starter bar connected to a disposable mold stool;

FIG. 6 is a partially cutaway enlarged side elevational view of the top end of the starter bar;

FIG. 7 is a front view of a hinged chillbox;

FIG. 8 is a side view of the hinged chillbox of FIG. 7, but with the starter bar attached;

FIG. 9 is an isometric view of a curvature-compensating connector for pulling the starter bar through bending rolls;

FIG. 10 is a side view of the bottom end of the starter bar showing the curvature-compensating connector; and

FIG. 11 is a cross-sectional view taken along line XIXI of FIG. 10.

Referring now to the drawings The flexible starter bar of my invention, designated generally 10, includes a head 12 which is releasably connected to a mold stool 14 having a recess or chillbox 15 therein. As shown in FIG. 1, starter bar 10 is positioned between opposing banks of guide rolls 16 which guide rolls 16 also act as bending and containment rolls. The mold stool 14 is positioned in a continuous-casting mold I8. Elongated continuous flexible metal facing pieces 20 and 21 are fixed to the head 12 of the starter bar. Facing pieces 20 and 21 are held in spaced parallel relation by an articulated separator comprised of a multiplicity of segments 23, such as tubular steel sections or round cornered square sections. Segments 23 are securely attached to the head 12 by a flexible connecting means 24, such as a tie rod, cable, or a link and pin arrangement. An anchor block 25 at the end of the tie rod holds the segments thereon. Each segment 23, as shown in greater detail in FIG. 2, has a number of holes 26 through which the tie rod passes. An alternative means for linking articulated segments 23 is shown in FIGS. 3 and 4. Flexible straps 28 are positioned in slots 29, cut in each end of the segments 23.

' No matter which connecting means is selected, some allowance is made forrotation of the segments. The necessary allowance may be attained merely by avoiding prestress in he connecting means, whereby the converting means can stretch to the necessary small extent. Otherwise, oversize holes or slots may be provided in the segments to permit the tie rods or straps to shift transversely.

As shown in FIGS. 5 and 6, facing pieces 20 and 21 are attached to head 12 by any suitable means, such as welding, riveting or'possibly bolting. The head 12 has a slot 31 and transverse holes 32. The slot receives a flange on the bottom of the mold stool, while the holes receive retaining pins 33 which secure bar to the mold stool 14. Head 12 is bored and recessed at 34 to provide an anchor for flexible connecting means 24. i

While the invention is readily used with a conventional chillbox which is integral with a mold stool as shown in FIGS. 1 and 5, it is preferable to use a chillbox that is hinged to a mold stool as shown'in FIGS. 7 and 8. Hinged chillbox 40 has a recess 41 with mushroom-type anchors 42 fixed therein. The chillbox is secured to a mold stool 44 by a hinge pin 46. The mold stool has an upwardly extending semicylindrical central portion 45 with a hole 47 bored longitudinally along its axis. semicylindrical legs 48 with coaxial holes 49 extend downwardly from each end of the chillbox. The configuration of the upstanding portion of the mold stool and the legs of the chillbox allow the chillbox to bend with respect to the mold stool when being conducted through the guide rolls 16. A leg 50 which projects downwardly from mold stool 44 has holes 51 to receive pins which will retain the mold stool in engagement with the head of the starter bar.

The ends of facing pieces and 21 remote from head 12 are bent toward each other, as shown in FIG. 1, to form a generally tapered structure to .facilitate movement of the starter bar through the various components of the continuouscasting machine.

Alternatively, as shown in FIGS. 9, 10 and 11, my starter bar may have a novel means 52 for pulling it through the guide rolls. This means comprises central base 53, transverse members 54 and abbreviated receptacles 56. Facing pieces 20 and 21 have angular extensions 58 and 59, respectively, the free ends of which protrude into the cavities of receptacles 56. The fixed ends of the extensions are contacted by crossmembers 54. The base 53 has a hole 60 therein for attachment of a pulling means, such as a cable. a

In operation flexible starter bar 10 is attached to a mold stool 14 or 44 and is positioned with the chillbox forming the bottom of the mold in a continuous-casting machine. The flexible starter bar assumes the radius of curvature dictated by the guide rolls 16. Because flexible facing pieces 20 and 21 are not connected to each other nor to any of the segments 23 of the articulated separator, each is free to move relative to the other. This freedom from restriction results in the piece having the smaller radius of curvature appearing to be longer than the piece with the larger radius of curvature when the tip of such piece reaches the horizontal position. Regardless of the radius of curvature chosen for the guide roll system, the guide rolls will-contact a continuous smooth surface of the starter bar.

If desired, a lubricating compound may be applied to all faying surfaces to ensure greater flexibility of the starter bar.

The continuous-casting operation is begun by teeming molten metal into mold 18. When the bottom of the column of molten metal contacts the chillbox, it solidifies and adheres thereto. A positive mechanical connection is assured by the use of anchors 42 in the chillbox. Then the starter bar is withdrawn to remove the metal casting from the mold, and is caused to pass through the bending rolls l6, pinch rolls 63, and straightening rolls (not shown) of the continuous-casting machine to conduct the casting to a horizontal position from which the hot casting can be cut to any desired length. Pinch rolls 63 and other pinch rolls (not shown) provide the withdrawal force for the starter bar shown in FIG. 1. Bar) of FIG. 10 is withdrawn by a cable secured to hole 60 of pullingv means 52 which is wound on a winch (not shown). As tension is increased in the cable, transverse member 54 engages angu lar extension 59 of facing piece 21 and pulls the starter bar Since the pulling member 52 is neither flexible nor hinged, l

have given it a generally tapered contour to enable it to pass through'a curved guide roll path withoutbecoming jammed.

After each continuous-casting operation when the starter bar has served its purpose to conduct the casting to a horizontal runout table, the chillbox 40 or mold stool 14 is removed from the starter bar by removing its hinge pin 46 orretaining.

pins 33, and is permitted to remain connected to the end of the casting which is subsequently cropped. After a new chillbox is connected to the starter bar,the starter bar is ready to be used again.

From the foregoing, it will now be apparent that the starter bar of the invention constitutes a flexible element, with a head which supports a temporary mold bottom, which is sufficiently rigid to be pushed upwardly through the guide rolls, and sufficiently flexible to travel between and conform to the path defined by the guide rolls, pinch rolls, nd straightening rolls, yet presents a smooth continuously curved surface to such rolls. 1 have also provided a pivotally attached chillbox for in conjunction with a flexible starter bar, which chillbox will pass through a curved guide roll system without causing strain or other damage to the roll system.

I claim:

1. A flexible starter bar for continus-casting, said'bar comprising a rigid head adapted to be removably attached to a mold stool, a pair of elongated spaced flexible facing pieces attached to said head, said facing pieces being held in spaced relation by an articulated separator comprised of a multiplicity of spacing members between said'facing pieces and in line contact with said facing pieces, and flexible connecting means passing through said spacing members and joining them to said head. v

2. A flexible starter bar as defined in claim 1 in which said connecting means comprises a plurality of wire ropes.

3. A flexible starter bar as defined in claim 1 in which said connecting means comprises a plurality of metal rods.

4. A flexible starter bar as defined in claim 1 in which said connecting means comprises a pair of flexible metal straps.

5. A flexible starter bar as defined in claim 1 in which said spacing members comprise a plurality of steel cylinders.

6. A flexible starter bar as defined in claim '1 further comprising an anchor block attached to said connecting member at the end remote from said head.

7. A flexible starter bar as defined in claim 6 further comprising an angular extension attached to the inside of the end of each of said facing pieces remote from said head and a pulling member attached to said extensions, whereby said pulling member is in contact with both of said facing pieces when the bar is straight and said pulling member is in contact with the one of said facing pieces having the greater radius of I curvature when the bar is curved.

8. A flexible starter bar as defined in claim 7 in which said pulling member comprises a base, a transverse member attached to said base, and a pair of receptacles attached to said base to receive said extensions.

9. A flexible starter bar as defined in claim 1 in which said facing pieces are continuous from said head to the end of said bar remote from said head.

10. A flexible starter bar as defined in claim 1 in which the ends of said facing pieces remote from said head are bent toward each other to form a tapered structure. 

1. A flexible starter bar for continus-casting, said bar comprising a rigid head adapted to be removably attached to a mold stool, a pair of elongated spaced flexible facing pieces attached to said head, said facing pieces being held in spaced relation by an articulated separator comprised of a multiplicity of spacing members between said facing pieces and in line contact with said facing pieces, and flexible connecting means passing through said spacing members and joining them to said head.
 2. A flexible starter bar as defined in claim 1 in which said connecting means compriSes a plurality of wire ropes.
 3. A flexible starter bar as defined in claim 1 in which said connecting means comprises a plurality of metal rods.
 4. A flexible starter bar as defined in claim 1 in which said connecting means comprises a pair of flexible metal straps.
 5. A flexible starter bar as defined in claim 1 in which said spacing members comprise a plurality of steel cylinders.
 6. A flexible starter bar as defined in claim 1 further comprising an anchor block attached to said connecting member at the end remote from said head.
 7. A flexible starter bar as defined in claim 6 further comprising an angular extension attached to the inside of the end of each of said facing pieces remote from said head and a pulling member attached to said extensions, whereby said pulling member is in contact with both of said facing pieces when the bar is straight and said pulling member is in contact with the one of said facing pieces having the greater radius of curvature when the bar is curved.
 8. A flexible starter bar as defined in claim 7 in which said pulling member comprises a base, a transverse member attached to said base, and a pair of receptacles attached to said base to receive said extensions.
 9. A flexible starter bar as defined in claim 1 in which said facing pieces are continuous from said head to the end of said bar remote from said head.
 10. A flexible starter bar as defined in claim 1 in which the ends of said facing pieces remote from said head are bent toward each other to form a tapered structure. 